Skip to main content
🇩🇪GDPR-compliant
Find the right

JSON Expert

for reliable data exchange, matched in minutes from over 15,000 CVs

Hire experts who design data contracts, validate API payloads, and transform JSON across applications, with fast, precise matching to vetted and available freelancers.

Meet FRATCH Experts who have recently used JSON

Verified expert

Lutz E.

View profile

Software Engineer Full-Stack (React/Next.js, TypeScript, C#/.NET, Python, Node.js)

Solingen
Lutz E.

Last position:

Freelance Software Developer – GoPro MultiCam Control via COHN at Plutos Company UG

  • Developed a pilot system to control and monitor multiple GoPro cameras
  • Implemented start, stop, status, media, download and diagnostic functions via COHN endpoints
  • Built camera detection, individual and group control, and stable session/KeepAlive logic
  • Set up a download pipeline with a queue, retry handling and temporary files
  • Ensured consistent session, folder and file naming for multicamera recordings
  • Integrated provisioning, certificates and network operations
Verified expert

Michael S.

View profile

IT & Test Consultant

Mainz
Michael S.

Last position:

IT & Test Consultant at Testing Experts GmbH

AI Readiness - Part 3: Creating an e-book on the use of AI in software testing

  • Designed and created an e-book on the sensible and safe use of AI in software testing from the perspective of an experienced test expert.
  • Used generative AI (ChatGPT, Perplexity Pro) as a sparring partner for structuring, wording suggestions and creating variations, with all content finally reviewed and approved using my own expertise.
  • Developed practical insights into the opportunities and risks of AI in testing, with a special focus on collaboration between testers and AI instead of “tester vs. AI”.
  • Title: “11 starke Gründe: Dream-Team statt Rivalen - Tester und KI sind gemeinsam unschlagbar”
  • Subtitle: “Wie Mensch und Maschine im Softwaretest das perfekte Team bilden – und warum reines KI-Testing riskant ist.”
  • Planned use of the e-book as a basis for workshops, customer meetings or internal training.
  • Technology: Generative AI, ChatGPT, Perplexity Pro, Microsoft Word, Adobe Acrobat, many years of hands-on professional testing experience, common sense.
Verified expert

Franz B.

View profile

Program Lead • Portfolio Manager • Digitalization & Transformation

Munich
Franz B.

Last position:

Product Development (AI) at Self-initiated

AI phone assistant platform

Claude Code, Google AI Studio, Python, LLM / Voice-AI, PostgreSQL

  • Designed and hands-on developed an AI-powered phone assistant platform (Voice-AI / LLM)—from idea and architecture through to MVP/product.
  • Built agentic workflows and end-to-end automations with Claude Code and Google AI Studio.
  • Also supported AI-powered delivery in client engagements: using Claude Code for governance documentation, requirements drafts, and automations.
Verified expert

Reinhold M.

View profile

Business Analyst, Proxy PO, Epic Owner, Quality Assurance

Petershausen
Reinhold M.

Last position:

Business Requirements Engineer, Proxy Product Owner, Tester at AXA Konzern AG

Working Environment

  • Insurance / Claims Management (Property, Liability, Automotive)
  • REST-based ClaimAPI with Guidewire ClaimCenter

Scope

  • Further development of the internal REST-based ClaimAPI with Guidewire ClaimCenter as the backend and various portals/front-end offices as clients, and with the following objectives: + increased AI-supported claims processing outside of Guidewire ClaimCenter + and support for all lines (property, liability, automotive).
  • Further development of automated claims processing

Activities

  • Interfacing IT & Business
  • Design activities with documentation in Confluence, Jira: + Requirements engineering (functional and non-functional) + Design of REST endpoints and coordination with interface partners (esp. AI-colleagues) + Identification, design and evaluation of alternative solutions (moving away from a monolithic approach toward fine-grained endpoints, with code reuse across all lines if possible) + Creation / refinement of product backlog items in Jira, i.e. epics, user stories and tasks, incl. alignment with developers & POs during (pre-)refinement sessions + Using AXA Secure GPT when creating / refining user stories (description, acceptance criteria) and designing REST endpoints + Estimation and prioritization of user stories and tasks during Sprint Planning sessions + Coordination and support during the implementation of Product Backlog items + Driving decision making with preparation and presentation of decision-making documents
  • Quality assurance: + Test management, including test case creation using Xray in Jira + Test execution using Bruno as REST client and in Guidewire ClaimCenter + Submission of test artifacts for PO approval + Analysis of production bugs

Methods Big Room Planning (aka PI-Planning in SAFe), Scrum, BPMN, EPK, UML, ERM, DDD

Tools / Tech Stack Teams, Confluence, Jira with Xray, OpenAPI/Swagger, REST, JSON, XML, MS Office, Bruno, GitHub repository (reading), Guidewire ClaimCenter, AXA Secure GPT (AXA's in-house GenAI solution based on Azure OpenAI)

Verified expert

Robert D.

View profile

Software Architect

Lübeck
Robert D.

Last position:

Java Software Architect at adesso insurance solutions GmbH

Verified expert

Fadi S.

View profile

Operational AI & Data Engineering Consultant

Oberhausen
Fadi S.

Last position:

Data Scientist at E-Commerce

  • Designed and developed a production-ready data platform based on Microsoft Fabric for an e-commerce company
  • Built a scalable Medallion Architecture (Bronze, Silver, Gold) with Lakehouse and Delta Lake as the foundation for analytics and AI applications
  • Developed a metadata-driven ETL platform with PySpark and a generic Incremental Loading Framework (SQL Server → Bronze → Silver → Gold)
  • Developed reusable components for Microsoft Fabric Notebooks to standardize data integration, transformation, and validation
  • Implemented automated data pipelines including monitoring, logging, error handling, and Delta MERGE strategies for stable production operations
  • Built a business layer architecture for reporting, data warehousing, and reusable data products
  • Integrated heterogeneous data sources via SQL Server, REST APIs, Amazon SP API, and Google Analytics 4
  • Worked closely with business departments to analyze business requirements and translate them into scalable data architectures

Technologies: Microsoft Fabric, PySpark, Python, SQL Server, Delta Lake, Lakehouse, OneLake, Data Factory, Data Warehouse, REST APIs, Amazon SP-API, Google Analytics 4

Verified expert

Niko S.

View profile

Developing Architect / Solution Architect

Hamburg
Niko S.

Last position:

Developing Architect, Technical Lead "gridlytics" at HH Energienetze

  • Built a data integration platform for high-, medium- and low-voltage assets to enable contextual analysis of time series with master data from SCADA control systems (IEC 60870 104), INIS and SAP.
  • Responsible for the architecture and implementation of the solution, and acted as a sparring partner for the Product Owner.
  • Technologies used: Kotlin, Spring Boot, Maven, TimescaleDB, PostgreSQL, liquibase, Elements IoT, Docker, Kubernetes, Grafana, Python, jupyter and various API gateways.
Verified expert

Bruno P.

View profile

Independent Consultant for Digital Products & Processes

Freilassing
Bruno P.

Last position:

Product Owner

Design and implementation of a “unified-commerce” platform for SMEs to sell and deliver multi-product bundles

Achievements: Designed and delivered a fully functional, CPQ-based “buy flow” process for configuring and selling multi-product bundles on time, and secured customer approval within the specified 90-day timeframe. Successfully tested the integration of various interface services for customer search, customer data enrichment, address validation, service qualification, phone number validation, credit checks, appointment selection and quote-to-order transition.

Responsibilities:

  • Strategic goal delivery: Translating strategic customer goals into action and delivering them (e.g. release content, business value).
  • Backlog management: Creating and refining backlog items (Initiatives, Epics, User Stories, Defects) in close coordination with the project team and client.
  • Prioritization & releases: Owning Product Backlog prioritization and delivery of defined release goals.
  • Deliverable tracking: Tracking work completed by suppliers and the client.
  • Roadmap & release planning: Developing and delivering roadmaps and release plans together with the client.
  • Scope ownership: Owning the contractually agreed scope of work.
  • Claim management: Proactive claim and change management with the client.
  • Team coordination: Managing and coordinating the development team.
  • Leveraging synergies: Using synergies between client projects and product development.
  • Proposal preparation: Preparing proposals (with supervision) and presenting them in person to clients and partners.

Skills: Developing, communicating and delivering product visions; Product Backlog Management; Stakeholder Management; Regular reporting to management and steering committees; Requirements analysis & engineering; Planning and documenting workshops; Functional leadership and coordination of (distributed) project teams and external service providers; Epic Management; User Story specifications; Creating use cases, supporting software testing and User Acceptance Testing (UAT); Release Management and sprint planning; TO-BE process design; Process optimization; Planning, designing and specifying interfaces to existing and new systems; Identifying, assessing and managing project risks; Proactive claim and change management; Facilitating sprint planning and reviews; Data migration; Scrum; Kanban; REST API; JSON; XML; BPMN; UML; Jira; Confluence

Verified expert

Vili D.

View profile

Senior Data Engineer, Data Architect, Software Developer

Neuenhagen
Vili D.

Last position:

Technical Lead, Data Engineer at Mercedes-Benz Consulting

  • Optimized the data architecture (Medallion) to better decouple processing steps and improve transparency and reproducibility

  • Ensured the technical quality of data processing in Databricks by introducing schema enforcement, data quality checks, and a structured data architecture

  • Pipeline orchestration with Azure Data Factory

  • Improved and automated the development and deployment process by integrating Git and GitHub Actions

  • Technical leadership of the Data Engineering team (3 employees)

  • Led workshops to optimize and stabilize the data platform and development process

  • Collected and prioritized new requests and maintained the product backlog

  • Technologies: Microsoft Azure (Data Lake, Data Factory), Databricks, Apache Spark (PySpark), Python, SQL, Git, Confluence, Power BI, Power Apps, Dataverse, MS Sharepoint, Mural

Verified expert

Jan F.

View profile

Senior IT Project Manager & Business Epic Owner

Munich
Jan F.

Last position:

Business Epic Owner – Central Master Data for Business Customers at Telco Group (B2B / Enterprise IT Services)

Overall business responsibility for a program-wide initiative to create a central, authoritative data foundation for business customer master data (contacts and locations) within an IT service management transformation program.

  • Managed the Epic portfolio from exploration through launch; prioritization and quarterly planning in a SAFe environment
  • Aligned business units, architecture, and IT delivery around a shared vision and clear rules for data ownership (Data Governance)
  • Prepared and secured scope and key decisions with program leadership, including deliberate descoping
  • Managed risks, dependencies, and escalations; reported to program leadership and the PMO
  • Developed the 2027 roadmap as a basis for budget and portfolio planning

Result: a clear MVP scope, key decisions made, and a 2027 roadmap. The program continued after handover without any loss of knowledge.

Verified expert

Onur K.

View profile

AI & Automation Consultant · Project Manager for AI Projects

Braunschweig
Onur K.

Last position:

Project Manager & Outsourcing Manager at SENEC GmbH (EnBW Group)

  • Built a scalable nearshore IT developer hub (Croatia, Czech Republic, Poland) as an independent company through a BOT model (Build – Operate – Transfer)
  • Identified, selected, and managed full-service agencies; introduced management and control mechanisms, including KPIs, SLAs, and regular service reviews
  • Prepared and reviewed data processing agreements and framework contracts in coordination with Legal & Compliance; integrated regulatory requirements (including KRITIS) into process design
  • Advised on cloud vs. on-premise strategies, data storage, and authorization concepts; supported Procurement with tendering and service provider evaluations
  • Managed change and process harmonization between internal teams and nearshore partners; reported to executive management, CFO, and CIO

Result: Scalable IT developer hub with an audit-ready governance model, reduced operating costs, and accelerated product development.

Verified expert

Mahmoud Q.

View profile

Information Security & GRC Expert

Hamburg
Mahmoud Q.

Last position:

Information Security & GRC Expert at GLG (Gerson Lehrman Group)

As a Council Member at GLG (Gerson Lehrman Group), the world’s leading expert network, I provide organizations, investment firms, and consulting companies with expert discussions on demand – wherever specialized knowledge in information security, IT governance, and regulatory compliance is needed.

My assessments are based on many years of practical experience in highly regulated industries: from building and implementing information security management systems (ISMS according to ISO 27001), IT risk and vulnerability management, and business continuity (ISO 22301) to the practical implementation of European regulations such as DORA, NIS2, BAIT, and the Cyber Resilience Act (CRA).

The cooperation is project- and discussion-based. I provide decision-makers with a practical perspective gained from real-world experience on cyber risks, security governance, and operational resilience – exactly when it is needed.

Verified expert

Frank S.

View profile

Freelance Unity 3D/ WebGL / C# / TypeScript / WPF / .NET Developer

Hamburg
Frank S.

Last position:

Skat Pro at Spiele Palast

Skat Pro

Redesign and modernization of an existing game application for various clients (web and mobile)

Technologies:

  • Unity 3D
  • C#
  • .Net
  • WebGL
  • Android
  • iOS
Verified expert

Ajay C.

View profile

Software Developer & AI Engineer | Python, RESTful APIs, CI/CD, DevOps

Braunschweig
Ajay C.

Last position:

Software Engineer & Cloud AI Developer at TANGILITY GmbH

Built Python-based AI microservices and integrations for an AEC/VR Unity-based SaaS app, focusing on LLM/VLM capabilities, retrieval-backed systems, RESTful APIs, containerized deployment, and an automation microservice for the CAD-to-Unity pipeline.

  • Developed a custom Hybrid A* based algorithm in C# to simulate hospital scenarios, detect early-stage design conflicts using collision/spatial data, and generate structured reports.
  • Solved and automated the time-consuming task of converting CAD files into usable Unity environments with a custom real-time pipeline. Used a ZeroMQ-based communication layer to distribute workloads across multiple processes and achieve real-time performance.
  • Built a Dockerized FastAPI pipeline for CAD-to-Unity automation, combining vision-based object matching, image embeddings, and precomputed metadata to automatically map CAD objects to Unity behavior scripts, assign properties, and reduce repeated AI inference calls.
  • Created documentation and examples to help technical users understand, configure, and extend the AI automation pipeline.

Discover over 15,000 top freelancers

Statistics of experts using JSON

Aggregated from the professional profiles of matched freelancers.

Experience

19 years

JSON experts have 19 years of professional experience on average.

Position duration

5.2 years

JSON experts stay in a single position for 5.2 years on average.

Positions per freelancer

14

JSON experts have completed 14 positions on average over the course of their careers.

Top business areas

Information Technology, Product Development, Quality Assurance

JSON experts have gathered most of their hands-on project experience in Information Technology, Product Development, and Quality Assurance.

Top industries

Information Technology, Banking and Finance, Automotive

JSON experts are most in demand in Information Technology, Banking and Finance, and Automotive.

Certification focus areas

Information Technology, Product Development, Project Management

JSON experts earn their certifications most often in Information Technology, Product Development, and Project Management.

Bachelor's degree or higher

89%

89% of JSON experts hold at least a Bachelor's degree.

Master's degree or higher

57%

57% of JSON experts hold at least a Master's degree.

Doctorate

10%

10% of JSON experts have a doctorate (PhD).

Certifications per freelancer

2

JSON experts hold 2 professional certifications on average.

Most common languages

German, English, French

JSON experts most often speak German, English, and French.

Speak two or more languages

98%

98% of JSON experts speak two or more languages.

Based on our profile pool as of 5 Nov 2026.

Daily rate distribution

0% 25% 50% 75% 100%
5% of JSON experts charge less than €400 per day.
51% of JSON experts charge between €400 and €800 per day.
39% of JSON experts charge between €800 and €1200 per day.
4% of JSON experts charge between €1200 and €1600 per day.
1% of JSON experts charge €1600 or more per day.
<€400 €400-​800 €800-​1200 €1200-​1600 €1600+

The chart shows how the daily rates of experts in this technology are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows the share of experts charging within that range.

Average rates of experts using JSON

Rates are based on recent contracts and do not include FRATCH margin.

800
600
400
200
Rate comparison chart
Daily rate avg. 755 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

800
600
400
200
Rate comparison chart
Median rate 760 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Calculated based on our freelancers’ daily rates as of 5 Nov 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.

JSON experts industry focus

See which industries our matched freelancers work in most often — every figure is calculated live from the freelancers on FRATCH.

  • Information Technology (95%)
  • Banking and Finance (46%)
  • Automotive (44%)
  • Manufacturing (43%)
  • Healthcare (37%)
  • Professional Services (35%)
  • Retail (35%)
  • Telecommunication (34%)

Please note that freelancers can work across multiple industries, so percentages overlap.

About the technology

Data Exchange

JSON, short for JavaScript Object Notation, is a lightweight text format for representing structured data. Its objects, arrays, strings, numbers, booleans, and null values make information easy for applications and people to read. Companies use it to move data between browsers, services, databases, and third-party systems.

APIs and Services

JSON is the standard payload format for many REST APIs and is also common in GraphQL responses, webhooks, and event-driven integrations. Specialists define request and response structures, handle nested resources, and keep contracts stable as services evolve. They connect front-end applications, mobile products, SaaS tools, and backend services through clear data models.

Schemas and Validation

Reliable JSON requires more than correctly placed braces and quotation marks. JSON Schema helps teams describe required properties, data types, allowed values, nesting rules, and reusable definitions. Experts use schema validation, contract tests, OpenAPI documentation, and linting to catch malformed or incompatible payloads before they reach production.

Ecosystem and Tooling

JSON work appears across JavaScript and TypeScript applications, Python, Java, C#, Go, PHP, and many other environments. Common tools include jq, Postman, Swagger Editor, OpenAPI tooling, serializers, parsers, validators, and command-line utilities. Professionals also work with UTF-8 encoding, date and number handling, escaping, streaming, and large-payload performance.

When Expertise Helps

  • Integrating a public API, payment service, CRM, or ERP
  • Replacing inconsistent XML, CSV, or custom data formats
  • Introducing schemas and contract testing across services
  • Debugging failed requests, encoding issues, or unexpected fields
  • Migrating data between applications or storage systems

Freelance expertise is useful when integrations are business-critical, documentation is incomplete, or several teams must agree on a shared contract. A specialist can establish conventions without forcing a complete platform rewrite.

Strong Professionals

Strong JSON professionals understand the systems behind the payload, not only the syntax. They distinguish missing, null, empty, and incorrectly typed values; protect sensitive fields; and design changes that remain compatible with existing consumers. They explain trade-offs clearly, test real edge cases, and leave practical schemas, examples, and documentation for the team that will maintain the integration.

Published on:
FRATCH GPT

FRATCH GPT delivers freelancer proposals with clear reasoning and transparent pricing in minutes, helping your hiring department quickly and compliantly find the best talent.

Give it a try:

Try FRATCH GPT

Frequently asked questions

Need clarity? These are the questions we hear most often about JSON.

JSON is used to exchange structured data between web applications, mobile apps, APIs, microservices, databases, and external vendors. It is also common in configuration files, event messages, webhooks, and data exports.

JSON is usually more compact and easier to work with in application code than XML, especially for nested objects and API responses. CSV is simpler for flat tabular data, but it does not represent relationships, arrays, or nested structures as naturally.

A strong JSON specialist should understand HTTP, REST, authentication, OpenAPI, JSON Schema, and API testing. Depending on the project, useful adjacent skills include JavaScript or TypeScript, SQL, message queues, cloud services, and data migration.

JSON syntax is easy to learn, but complex integration work requires practical experience with versioning, validation, error handling, security, and backward compatibility. The right level depends on whether the assignment involves a small payload change or shared contracts across many services.

JSON work is often well suited to remote collaboration because teams can share schemas, API specifications, test collections, and sample payloads online. Clear ownership, written decisions, and access to staging systems matter more than physical proximity.

Review whether the JSON design is consistent, documented, validated, and safe for future changes. Ask for examples of schema decisions, error responses, compatibility testing, handling of null values, and protection of sensitive data.

JSON Schema is valuable when several services or teams exchange the same data, or when payload errors are costly. It defines structure and constraints that can support validation, documentation, generated types, and contract tests.

Experienced JSON professionals resolve malformed payloads, inconsistent field names, incorrect data types, encoding problems, deep nesting, and breaking API changes. They also improve parsing performance and make integrations easier to monitor and maintain.

The average hourly rate of freelancers who have used JSON in their recent projects is 94 €, which corresponds to a daily rate of about 755 € based on an 8-hour working day.

Of the freelancers who have used JSON in their recent projects, 89% hold at least a Bachelor's degree, 57% hold at least a Master's degree, and 10% hold a doctorate.

On average, freelancers who have used JSON in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 5.2 years.

The most common languages among freelancers who have used JSON in their recent projects are German (98%), English (97%), and French (15%).

The most common industries among freelancers who have used JSON in their recent projects are Information Technology (95%), Banking and Finance (46%), and Automotive (44%).

The most common business areas among freelancers who have used JSON in their recent projects are Information Technology (99%), Product Development (90%), and Quality Assurance (63%).

Main locations of FRATCH Experts, who have recently used JSON

Our freelancers and interim experts are at home all over Germany — available on-site in Berlin, Hamburg, Munich and every major business hub, or fully remote. Choose a city to discover matched specialists, local market insights and up-to-date availability.

In Austria our freelancers and interim experts support companies from Vienna to Graz — on-site where your project needs them, or fully remote. Choose a city to discover matched specialists, local market insights and up-to-date availability.

Across Switzerland our specialists are active in Zurich, Geneva, Basel and Bern — working on-site or fully remote. Choose a city to discover matched specialists, local market insights and up-to-date availability.

Zurich Geneva Basel Bern

Countries:

Request a free demo

Get in touch with the FRATCH team and we will get back to you within 4 hours.

Contact form

Would you rather directly get in touch?
We always have the time for a call or email!

FRATCH CEO avatar

Philipp Thomaschewski

FRATCH CEO

LinkedInFRATCH